Background: This study was formulated to compare the effect of 5%hydrofluoric acid in comparison to 37%phosphoric acid with and without the application of silane on bond strength of composite to porcelain. Materials and Methods: Specimen preparation was divided in to two phases, metal-disks fabrication (8mm-diameter and 4mm-thickness) and ceramic veneering. Thirty two specimens were prepared, sandblasted with 50 μm aluminum oxide, and divided into four groups of eight samples. Groups I and III were etched with 37%phosphoric acid while groups II and IV were etched with 5%hydrofluoric acid; and groups I and II were silaneted while groups III and IV were not. Heliobond, and resin composite were applied to each specimen using a plastic transparent split mold (4mm- diameter and 4mm-height). Specimens were stored in distilled water for 24 hours then thermocycled for 100 cycles. Shear bond strength was determined by a Zwick universal machine at a cross-head speed 5 mm/minute. Results: Mean shear bond strength values were 21.02(group I), 23.31(group II), 4.00(group III), and 18.60(group IV). Paired-t revealed that specimens treated with 5%hydrofluoric acid were significantly higher than those treated with 37%phosphoric acid regardless the use of silane. The use of silane dramatically enhanced the bond strength of composite resin to porcelain for both acids. All specimens treated with 37%phosphoric acid without silane showed adhesive failure, while those treated with 5%hydrofluoric acid showed mostly cohesive failure within ceramic. Conclusion: Silane improved the shear bond strength of composite to ceramic, and hydrofluoric acid performed greater bond strength compared to phosphoric acid.
Background: The success and maintenance of indirect dental restorations is closely related to the marginal accuracy, which is affected by many factors like preparation design, using of different fabrication techniques, and the time of taking final impression and pouring it. The purpose of this in vitro study was to evaluate the effect of different pouring time of conventional impression on the vertical marginal gap of full contour zirconia crowns in comparison with digital impression technique. Materials and Methods: Forty sound recently extracted human permanent maxillary first premolar teeth of comparable size and shape were collected. Standardized preparation of all teeth samples were carried out to receive full contour zirconia crown re
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In the name of of Allah the Merciful
Introduction:
Praise be to Allah, Lord of the Worlds, and prayers and peace be upon our master Muhammad and his family and companions.
After
I have looked at a part of the jurisprudence of Hajj jurisprudence, which is needed now, especially after it facilitated travel to perform Hajj and Umrah, so the need was an advocate and a list for writing in it, which is beneficial to Hajj, Umrah and the guide.
And this important part is the things that contravene the woman's man in the Hajj and after the search and tracking found that there are ten things that get the violati
... Show MoreThe Noble Qur’an is the book of God, the Blessed and Exalted, in which is the teachings of God Almighty’s religion, which is Islam, in order for people to unite it and establish servitude to it. The individual and the society alike saw it appropriate to make my opinion alerting the seriousness of this matter, so the research was entitled (The Impact of Sins and Disobedience on the Individual and Society in the Holy Qur’an - Objective Study), knowing that we touched upon some of the effects, which we found it appropriate to mention in this research in the service of the good. Its details came in the Holy Qur’an without referring to others, noting their arrangement in the Holy Qur’an..
This research examines the quantitative analysis to assess the efficiency of the transport network in Sadr City, where the study area suffers from a large traffic movement for the variability of traffic flow and intensity at peak hours as a result of inside traffic and outside of it, especially in the neighborhoods of population with economic concentration. &n
... Show MoreLaser drilling is capable of producing small, precisely positioned holes with high degree of reproductively. In this paper , IR millisecond Nd:YAG single pulsed laser was used to determine the effect of laser parameters on the drilled hole of the glass - fiber reinforced epoxy composite FR-4 sample of 2 mm in thickness . The type of laser source was GSI lumonics JK760TR Series laser 1.064μm system in a CNC cabin. The JK760TR series has a 0.3-50ms pulse length and a maximum repetition rate 500Hz with an average power of 600W. The investigation of single pulse laser drilling in this paper was based on theoretical and experimental solutions. In single pulse technique, the investigation included focal plane position fpp, pulse shap
... Show MoreThe present study was conducted to determine the pathogenicity of Paecilomyces farinosus as biocontrol agents against Tragoderma granarium (khapra) under laboratory conditions with three concentrations ( 2.8 x 108 , 2.8 x 106 ,2.8 x104 spores/ ml). The laboratory results revealed that fungi showed it's higher pathogencity to larve stage on 2nd instar and 6th instar , although their capability differs according to the fungi concentrations this fungi caused higher mortality of 2nd larval instar 70% and 60% ,55% when it was used at concentrations 2 .8 x 106 ,2.8 x104 spores/ ml respectively. On the other hand on 6th larval instars 55% , 35% , 30% at concentrations ( 2.8 x 108 , 2.8 x 106 ,2.8 x104 spores/ ml) respectively, and the h
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To achieve sustainability in the field of civil engineering, there has become a great interest in developing reactive powder concrete RPC through the use of environmentally friendly materials to reduce the release of CO2 gas produced from cement factories as well as contribute to the recycling of industrial wastes that have a great impact on environmental pollution.
In this study, reactive powder concrete was prepared using total binder content of 800 kg/m3, water to binder ratio (0.275), and micro steel fibers 1% by volume of concrete. The experimental program included replacing fly ash with (8, 12, 16) % by cement weight to find the optimal ratio, which achieved the best mechanical proper
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The specifications of lubricating oil are fundamentally the final product of materials that have been added for producing the desired properties. In this research, spherical nanoparticles copper oxide (CuO) and titanium oxides (TiO2) are added to SAE 15W40 engine oil to study the thermal conductivity, stability, viscosity of nano-lubricants, which are prepared at different concentrations of 0.1%, 0.2%, 0.5%, and 1% by weight, and also their pour point, and flash point as five quality parameters. The obtained results show that CuO nanoparticles in all cases, give the best functionality and effect on engine oil with respect to TiO2. With 0.1 wt. % concentration, the thermal conductivity of CuO/oil and TiO2/
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The aim of the present study is to investigate and compare the efficacy of L-carnitine, multivitamins and their combination therapies on semen characteristics in idiopathic male infertility. Idiophathic infertile patients were randomly divided into three groups who had received three different treatment regimens for three months: group A (45 patients) has received 2 grams daily of L-carnitine alone; group B (55 patients) had received the combination of L-carnitine (2 grams daily) plus one tablet daily of multivitamins (Stresstabs®); and group C (29 patients) had received one tablet daily of multivitamins alone. The study was started on 1/11/2009 and completed on 31/3/2010 and performed at Rizgari Teaching Hospital in
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